使背景伸展到内容的最大高度

Question

My codepen http://codepen.io/leongaban/pen/sBvfL

So having a strange issue, I'm trying to get the background of the #portfolio div to stretch to contain the thumbnails below which are in an ul list inside of the portfolio div.

However 100% or auto doesn't affect the height. I have to set a static height, like 1000px. To get the background to cover the thumbs. However I'm trying to not set a static height since the thumbnails will get longer.

Perhaps I've been coding this too long, how would you code this?

---

HTML

<div id="portfolio">

  <div class="portfolio-nav">
       <h1>Portfolio</h1>
  </div>

        <div id="showcase-holder">

            <div id="showcase-div">

            <ul id="portfolio-thumbs">

                <li>
                    <a href="/portfolio/chipestimate">
                        <img class="role-thumb" src="http://leongaban.com/images/thumb_chipestimate.jpg" alt="ChipEstimate"/>
                        </a><p>ChipEstimate</p>

                </li>

                <li>
                    <a href="/portfolio/shabang" title="Shabang">
                        <img class="role-thumb" src="http://leongaban.com/images/thumb_shabang.jpg" alt="Shabang"/>
                        </a><p>Shabang</p>

                </li>
        </ul>
    </div>
 </div>

CSS

body {
    background: brown;
}

#portfolio {
    position: relative;
    width: 100%;
    height: 50%;
    background: #fff;
    border-top: 2px solid #ccc;
    z-index: 1;
}

#portfolio ul { list-style: none; }

.portfolio-nav { margin: 0 0 20px 0; }

.portfolio-nav h1 {
    padding: 30px 0 10px 0;
    text-align: center;
    font-size: 2.5em;
    font-weight: 700;
    color: #d74927;
    text-shadow: 1px 1px #ccc;
}

#showcase-holder {
    position: relative;
    width: 80%;
    height: 100%;
    margin: 0 auto;
    border-bottom: 2px solid #ccc;
}

#portfolio-thumbs {
    position: relative;
    float: left;
    list-style-type: none;
    margin: 0 0 40px 0;
    padding: 0 0 0 5%;
    width: 100%;
    height: 100%;
}

#portfolio-thumbs li {
    position: relative;
    float: left;
    width: 20%;
    margin: 1%;
    text-align: center;
    padding: 5px 5px 15px 5px;
    background-size: 100% auto;
    overflow: hidden;
    background: white;
    -webkit-transition: background .3s;
    -moz-transition: background .3s;
    -ms-transition: background .3s;
    transition: background .3s;
}

#portfolio-thumbs li:hover {
    color: #fff;
    background: #d74927;
    -webkit-transition: background .5s;
    -moz-transition: background .5s;
    -ms-transition: background .5s;
    transition: background .5s;
}

#portfolio-thumbs li a {
    color: #333;
    text-decoration: none;
}

#portfolio-thumbs li p {
    padding: 10px 0 0 0;
}

#portfolio-thumbs li img.role-thumb {
    width: 95%;
    min-width: 170px;
    padding-top: 5px;
}

Answer 1

Parents will normally expand to the height of their children, though won't in case the children are relative.

• You can remove positions and floats to accomplish expanding.
• In order to expand a parentdiv based on positioned children try overflow: auto; on #portfolio. This will make #portfolio expand to the height of its children. As seen on this fork of your example.

overflow: auto; will actually let your browser decide, which normally renders this to overflow: hidden; . Though I tend to use overflow: auto; to prevent issues with scrollbars as the page possibly expands later on.

Answer 2

You have added float to your li elements, which means that the parent will not expand to contain these elements.

You can work around this by adding a clearing div .

<div style="clear:both;"></div>

after the showcase-holder div.

Answer 3

Adding overflow: hidden to both #showcase-div and #portfolio-thumbs should do it for you.

http://jsfiddle.net/5SFFP/